An electrocardiogram, also known by the acronym ECG, is the graphic representation of the electrical activity of the heart during its operation, which is recorded by way of electrodes applied on the surface of the body of a patient in the thoracic region.
Measuring heart electrical activity is based on a physiological principle. The onset of electrical impulses in the myocardium in fact causes potential differences varying over space and time that can be recorded through a plurality of electrodes contacting the body of a patient in predetermined locations known as “leads”. The conductive surface of the electrodes is covered with a suitable ionic gel decreasing the contact impedance between skin and electrode, while contact is favored by way of suction pads, bandages or the like applied to the individual electrodes, or by way of suitable chest belts on which a number of electrodes are mounted at predetermined positions. The registration of the potential differences by the electrodes is possible thanks to the conductivity of the interstitial fluids of the human body.
An electrocardiogram is a very effective tool for monitoring the electrical activity of the heart and for detecting mechanical or bioelectrical pathologies.
The electrodes of an electrocardiograph are connected to an electronic recording unit through respective electrical wires. The recording unit is for example a remote unit to which the electrical wires are connected. Therefore, when recording an electrocardiogram a patient is connected to the electronic recording unit through the electrical wires. This is rather uncomfortable, because the wires partially rest on the patient's body and must be carefully arranged by a doctor so that they do not interfere with each other.
In order to improve and simplify the connection mode between each electrode and the electrical recording unit there have been developed electrocardiographs including a connection unit that may be worn by a patient. Connection units are provided with a plurality of input connectors to which the electrodes may be connected, as well as with an output connector configured to allow connection of a single wire for the transmission of the data acquired through the electrodes to a remote electronic recording unit.
The publication US 2008/0177168 A1 e.g. discloses a device for recording an electrocardiogram comprising a plurality of electrodes that may be individually connected through respective electrical wires to a connection unit or “hub” that is arranged on the body of a patient. The electrode wires are extensible so as to allow positioning of the electrodes according to a desired lead arrangement. In addition to the connectors for the electrode wires, the electronic connection unit comprises a further connector which allows connection of a wire for the transmission of the data acquired through the electrodes to a remote recording unit.
Also known are wireless electrocardiographs wherein the electrodes are connected to a portable electronic unit that may be worn by a patient. The electronic unit is provided with a transmitter that allows data transmission to a fixed unit or base connectable to a monitoring equipment of a traditional type. The European patent EP 1467651 B1 describes an example of a device of this type.
The publication GB 2368127 A discloses another example of a wireless electrocardiograph that comprises an electronic unit and a chest assembly provided with a housing for the electronic unit and with a plurality of electrical wires with respective electrodes. The electronic unit is detachable from the chest assembly.
Also known are the so-called “Holter” electrocardiographs, from the name of their inventor, designed to monitor the electrical activity of the heart over long periods, for example 24 hours or a few days, during which a patient may lead a normal life. Holter devices comprise a plurality of electrodes that are connected to the body of a patient according to lead patterns that are similar to the lead patterns used for the recording of a traditional electrocardiogram, as well as a portable electronic unit configured to be worn by the patient. The portable electronic unit includes an electronic unit-configured for recording, storing and sending to a remote processing unit the data acquired through the electrodes.
Holter type electrocardiographs are generally more complex than those used for ambulatory recording of electrocardiograms, because they have to perform monitoring over much longer periods during which a patient may lead his life according to his normal habits. Consequently, electrical energy consumption problems must be carefully considered in the design of these devices.
Energy consumption is a very important problem even in non-Holter electrocardiographs, which carry out a real-time monitoring of a patient and are configured for the transmission of data in wireless mode, which results in a high consumption of energy.
The interaction of patients with known electrocardiographs, as well as data transmission and energy consumption may be improved. The technical problem underlying the present invention is therefore to provide an electrocardiograph which allows to overcome the drawbacks mentioned above with reference to the prior art.
This problem is solved by a device according to claim 1. Preferred features of the present invention are object of the dependent claims.